Each WIP Transaction that is failing will write to the server event log. But with IIS 7 the security has been redefined more stricktly and you will get first the following error on you client side : ASP.NET Cannot open log for source {0}. You may not have write access. – Access is denied. If the execution is failing again afterwards you will normally receive an Invalid Handle error. If this is the case, here’s my workaround :

1.    Run Regedit
2.    Add the “Authenticated Users” to the EventLog –> Application (not to a child)
3.    Give the permissions FullAccess to the Authenticated Users” and replace the permission on the child objects
4.    Add (A;; 0x3;;;AU) the CustomSD